Chlorella and spirulina are waterborne microorganisms that emerged as potent nutritional supplements. Let’s discover their differences and if one is superior to the other in terms of health benefits.

Chlorella vs. Spirulina: A Quick Background

Chlorella and spirulina are both types of algae with a noteworthy list of potential nutritional benefits. They provide a wide range of important vitamins, minerals, and antioxidants. It has also been studied that they may boost heart health and help regulate blood sugar levels. [1]

Although both have many similarities and are considered “superfoods” with their nutrient profile, they also have several differences worth noting.

What Is Spirulina?

Spirulina is a blue-green alga containing B-vitamins, beta-carotene, and vitamin E. It is often used as a vegan protein and iron source and is rich in other nutrients and phytochemicals.

Studies also show that spirulina may help in various health conditions such as high cholesterol and high triglycerides. Other potential benefits include weight loss, increased energy, and immune system stimulation.

What Is Chlorella?

Chlorella is also a nutrient-dense alga, but it’s part of the green algae family that grows in freshwater. Its wide range of nutritional content includes proteins, chlorophyll, dietary fiber, vitamins, and minerals.[2]

Here’s the thing: chlorella and spirulina have key differences in their processing for consumption. With spirulina, algae are cultivated in ponds, harvested through filters, then pressed and dried. If it doesn’t require to be ground into a fine powder, naturally dried spirulina is ready to eat.

Unlike spirulina, chlorella has to be taken as a supplement because it has these hard cell walls we cannot digest as whole food. Its processing requires the cell walls to be cracked and pulverized for it to be safe for consumption. This is why you can see that chlorella supplements have “open-cell” or “cracked cell” on the label.

This difference in the processing for consumption affected the popularity of chlorella. However, in recent years, chlorella has been used as food in Japan and a dietary supplement in the United States. It’s marketed as a “superfood” available in tablet, granule, extract, and powder forms.

Chlorella vs. Spirulina: Nutrient Profiles

chlorella vs spirulina

We already know that they both have amazing nutritional benefits—from the vitamins and minerals to their antioxidant properties. However, there are key differences in their nutrient profiles. 

Complete Protein Package

Sometimes it can be tricky to pick a diet in which we can get the “complete protein package” we need. A protein food source can be considered “complete” if it includes all the essential amino acids. 

The good thing is, the protein found in both spirulina and chlorella contains all essential amino acids. Although both of them contain high amounts of protein, studies state that spirulina may contain up to 10% more protein than chlorella.

To further visualize it, one tablespoon of spirulina can have up to 4g of protein for just 20 calories. Plus, it includes essential amino acids easily absorbed by our bodies. 

Based on the Dietary Reference Intake report for macronutrients, the protein requirement of a sedentary adult is 0.8 grams of protein per kilogram of body weight. This means that the average adult man should eat about 56g of protein per day and about 46g for women.

Although spirulina and chlorella are excellent protein sources, it’s also good to get the required amount of protein in various healthy food sources like fish, nuts, legumes, and beans. It would also be best to consult your nutritionist about your preferred changes in your diet.

Omega-3 Fatty Acids

It’s not a secret that omega-3 fatty acids have numerous benefits for our overall health and well-being.[4] They are essential nutrients because our bodies can’t make them, so we get them in the food we eat.

Chlorella and spirulina are rich in polyunsaturated fats, especially omega-3 fatty acids (DHA and EPA). The intake of these polyunsaturated fats has been studied to be associated with a lower risk of heart disease, especially when substituted for saturated fats (one of the unhealthy types of fat).[5]

Some of the health benefits of omega-3 fatty acids include reduction in inflammation, improved bone health, and lower risk of heart disease.[7] Although chlorella and spirulina contain various polyunsaturated fats, studies show that chlorella contains more omega-3 fatty acids than spirulina.[8]

Antioxidant Properties

As mentioned earlier, both chlorella and spirulina contain powerful antioxidants. These are compounds that help neutralize free radicals in our bodies to prevent damage to cells and tissues.

A study published in the American Chemical Society looked at the extracts of these algae and found out that spirulina had higher phenol content.[9] Phenolic compounds are important plant constituents with redox properties responsible for antioxidant activity.[10]

However, we can’t also ignore the antioxidant properties of chlorella and its ability to boost our body’s production of other antioxidants. A six-week study published in the National Library of Medicine supported the antioxidant role of chlorella and mentioned that it is a whole-food supplement essential in a healthy diet.[11]

Chlorella vs. Spirulina: Other Uses and Benefits

chlorella vs spirulina

Aside from their powerful nutrient profiles, chlorella and spirulina have other health claims supported by various studies. Some of them may have more evidence than others, but here’s what research says:

Benefits for High Cholesterol

To keep our heart healthy, we should increase our HDL (good cholesterol) and decrease LDL (bad cholesterol) and triglycerides. High levels of LDL are major risk factors for various cardiovascular diseases.

In a study published in Nutrition Journal, a daily 416-milligram dose of chlorella improved blood lipid levels in adults with moderately elevated cholesterol. The even better news is, aside from the significant reductions in total cholesterol, triglycerides, and LDL, there were also increases in HDL.[12]

Spirulina also has benefits for lipid disorders such as high cholesterol and triglycerides. The results of a research paper published in the Annals of Nutrition and Metabolism associated spirulina with significant reductions in cholesterol.[13]

Benefits of Chlorella in Hepatitis C

In a study published in the World Journal of Gastroenterology, the supplementation of chlorella in adults with chronic hepatitis C virus infection helped reduce liver inflammation levels.

This supports that chlorella may aid in addressing inflammatory symptoms, but it doesn’t have a role in altering the hepatitis C viral load. It can only help manage some symptoms but cannot treat the underlying infection.[14

Benefits of Spirulina in Diabetes


In a small study included in the Journal of Nutraceuticals, Functional, and Medical Foods, 2 grams of spirulina a day taken for two months reduced blood sugar, cholesterol, and triglyceride levels. These patients didn’t modify their existing diet or lifestyle, and they were not using insulin during the study.[15]

Benefits for Weight Loss

The benefits of chlorella and spirulina in weight loss still need further research and larger clinical trials. However, in a study published in the US National Library of Medicine, spirulina demonstrated several benefits for improving weight loss, dyslipidemia, and obesity.

This is due to its mechanism of action, which includes preventing hepatic fat accumulation, reducing oxidative stress, and improving insulin sensitivity and satiety.[16]

Chlorella and Spirulina: Possible Side Effects

Although both are considered safe and well-tolerated, they may still cause some side effects. It may also cause possible dangers for people with certain conditions such as autoimmune diseases and patients taking blood thinners.

Some common side effects of chlorella may include flatulence, nausea, stomach cramps, diarrhea, and green discoloration of stool. However, most of these side effects tend to disappear over time as your body adapts to the treatment.[17]

With spirulina, the few adverse events may include headaches, allergic reactions, muscle pain, sweating, and insomnia in some cases. Also, if you have a thyroid condition, autoimmune disorder, gout, kidney stones, metabolic disorders such as phenylketonuria, or are pregnant, you should consult with your doctor first before taking this supplement.

As with any supplement, it’s important to consult with your doctor, especially when you have a certain condition, disease, or allergy. Also, be sure to buy supplements from reputable brands that undergo third-party testing to ensure safety.

Chlorella vs. Spirulina: Which Is Better?

Although most of their nutritional compositions are very similar, chlorella appears to have a slightly higher amount of calories, omega-3 fatty acids, magnesium, iron, zinc, and some other essential vitamins and minerals. 

Spirulina may have higher amounts of protein, but some studies show that the amount of protein in chlorella is comparable. Spirulina also has higher copper content, but its deficiency in our bodies is quite rare.

Chlorella might have a slight advantage in some nutrients, but the difference may not be that significant. It will still depend on the amount you take and the consistency. 

Bottomline: Spirulina vs. Chlorella

Chlorella and spirulina are highly nutritious forms of algae that offer a wide variety of health benefits. Choosing between the two should not be too hard. As long as you consult with your doctor if there’s anything you’re unsure of, taking either chlorella or spirulina can have beneficial effects on your health.

Disclaimer: This article is only a guide. It does not substitute the advice given by your own healthcare professional. Before making any health-related decision, consult your healthcare professional.

Editorial References And Fact-Checking

  • Huang, H., Liao, D., Pu, R., & Cui, Y. (2018). Quantifying the effects of spirulina supplementation on plasma lipid and glucose concentrations, body weight, and blood pressure. Diabetes, metabolic syndrome and obesity : targets and therapy11, 729–742.
  • Bito, T., Okumura, E., Fujishima, M., & Watanabe, F. (2020). Potential of Chlorella as a Dietary Supplement to Promote Human Health. Nutrients12(9), 2524.
  • Clifton, P. M., & Keogh, J. B. (2017). A systematic review of the effect of dietary saturated and polyunsaturated fat on heart disease. Nutrition, metabolism, and cardiovascular diseases : NMCD27(12), 1060–1080.
  • Saini, R. K., & Keum, Y. S. (2018). Omega-3 and omega-6 polyunsaturated fatty acids: Dietary sources, metabolism, and significance – A review. Life sciences203, 255–267.
  • Kent, M., Welladsen, H. M., Mangott, A., & Li, Y. (2015). Nutritional evaluation of Australian microalgae as potential human health supplements. PloS one10(2), e0118985.
  • Wu, L. C., Ho, J. A., Shieh, M. C., & Lu, I. W. (2005). Antioxidant and antiproliferative activities of Spirulina and Chlorella water extracts. Journal of agricultural and food chemistry53(10), 4207–4212.
  • Aryal, S., Baniya, M. K., Danekhu, K., Kunwar, P., Gurung, R., & Koirala, N. (2019). Total Phenolic Content, Flavonoid Content and Antioxidant Potential of Wild Vegetables from Western Nepal. Plants (Basel, Switzerland)8(4), 96.
  • Lee, S. H., Kang, H. J., Lee, H. J., Kang, M. H., & Park, Y. K. (2010). Six-week supplementation with Chlorella has favorable impact on antioxidant status in Korean male smokers. Nutrition (Burbank, Los Angeles County, Calif.)26(2), 175–183.
  • Ryu, N. H., Lim, Y., Park, J. E., Kim, J., Kim, J. Y., Kwon, S. W., & Kwon, O. (2014). Impact of daily Chlorella consumption on serum lipid and carotenoid profiles in mildly hypercholesterolemic adults: a double-blinded, randomized, placebo-controlled study. Nutrition journal13, 57.
  • Park, H. J., Lee, Y. J., Ryu, H. K., Kim, M. H., Chung, H. W., & Kim, W. Y. (2008). A randomized double-blind, placebo-controlled study to establish the effects of spirulina in elderly Koreans. Annals of nutrition & metabolism52(4), 322–328.
  • Azocar, J., & Diaz, A. (2013). Efficacy and safety of Chlorella supplementation in adults with chronic hepatitis C virus infection. World journal of gastroenterology19(7), 1085–1090.
  • Mani, U. V., Desai, S., & Iyer, U. (2000). Studies on the Long-Term Effect of Spirulina Supplementation on Serum Lipid Profile and Glycated Proteins in NIDDM Patients. Journal of Nutraceuticals, Functional & Medical Foods, 2(3), 25–32.
  • DiNicolantonio, J. J., Bhat, A. G., & OKeefe, J. (2020). Effects of spirulina on weight loss and blood lipids: a review. Open heart7(1), e001003.
  • Azocar, J., & Diaz, A. (2013). Efficacy and safety of Chlorella supplementation in adults with chronic hepatitis C virus infection. World journal of gastroenterology19(7), 1085–1090.


  • Joanna Daluro

    Joanna is extremely passionate about empowering her readers to make informed health decisions. Her writing process involves intensive research and fact-checking, but she also enjoys writing health-related product-review articles that help readers make better choices. Her goal is to create highly-accessible and research-based content that readers can relate to and learn from. In her free time, Joanna loves reading self-help books.


Joanna is extremely passionate about empowering her readers to make informed health decisions. Her writing process involves intensive research and fact-checking, but she also enjoys writing health-related product-review articles that help readers make better choices. Her goal is to create highly-accessible and research-based content that readers can relate to and learn from. In her free time, Joanna loves reading self-help books.